1. (Field of The Invention)
This invention relates to a structure for improving the mechanical strength of a locking device, e.g., a hood lock or a door lock of a vehicle.
2. (Description of the Prior Art)
In the conventional hood lock device of a vehicle is constructed in general as follows.
That is, the device comprises a base plate secured to and depending substantially vertically from the vehicle body. The device also comprises a latch lever and a locking lever, these levers being pivotally mounted by respective pins on base plate. The latch lever is rotated in mesh with a striker entering a U-shaped notch, which is formed in the base plate such that it extends downwardly from the upper edge of the base plate when the hood is closed. The locking lever serves to engage with the latch lever to prevent the rotation of the latch lever.
Further, there are comprised a tension spring biasing the latch lever in the direction to detach the striker from the notch, a tension spring biasing the locking lever in the direction to cause engagement of the locking lever with the latch lever, a secondary latch lever pivoted by a pin on the base plate on the side thereof opposite the side where the locking lever being provided, an operating section of the secondary latch lever, a tension spring biasing in the direction, in which a secondary latch lever is engaged with the striker base provided on the hood, and a wire connecting the lower end of the locking lever and operating handle in the vehicle body.
This hood lock device operates as follows.
When the locking lever is turned from the state, in which the hood is closed, via the wire by pulling the operating handle in the vehicle body, the latch lever is released, whereby the striker is raised by the biasing force of the tension spring so that the hood is raised to a secondary latch position, at which the secondary latch lever is engaged with the striker base.
Subsequently, the operating section is pushed with a hand inserted through a gap between the front portion of the vehicle body and the front end of the slightly opened hood. Consequently, the secondary latch lever is rotated so that its upper end is detached from the striker base. Now, the hood can be opened perfectly.
When closing the hood, the striker base passes by causing displacement of the upper end of the secondary latch lever, while the striker is advanced into the notch of the base plate to cause rotation of the latch lever.
When the latch lever is rotated up to the position the locking lever is engaged with the latch lever to prevent rotation of the latch lever. The hood is thus held in a perfectly closed state.
With the prior art locking device having the above structure, when a sudden impact load is exerted in the direction to cause detachment of the striker from the notch of the base plate at the time of a collision of the vehicle or the like, the impact load is concentrated on the pins via the meshing portions of the latch lever and locking lever.
In such a case, portions of the base plate supporting the pins are liable to be deformed because the base plate made of a material, which does not provide a considerably high mechanical strength, although the latch lever and locking lever are imparted with high mechanical strength by annealing or like treatment. When the base plate is deformed, the pins are tilted to cause tilting of lower portions of the latch lever and locking lever away from the base plate. In such a case, the latch lever and locking lever are liable to be detached from each other due to the difference in the extent of tilting of the latch lever and locking lever.
Experiments prove that the latch lever has a greater tendency of tilting away from the base plate than the locking lever.
This invention has a purpose of providing a locking device for a vehicle, which is improved with an aim of solving the problem noted above.